@yubing744/rooch-sdk/src/utils/keypairs/ed25519/ed25519-hd-key.ts

Rooch SDK

// Copyright (c) RoochNetwork
// SPDX-License-Identifier: Apache-2.0

// This is adapted from https://github.com/alepop/ed25519-hd-key replacing create-hmac
// with @noble/hashes to be browser compatible.

import { sha512 } from '@noble/hashes/sha512'
import { hmac } from '@noble/hashes/hmac'
import nacl from 'tweetnacl'
// import { fromHEX } from '@mysten/bcs'
import { fromHexString } from '../..'

type Hex = string
type Path = string

type Keys = {
  key: Uint8Array
  chainCode: Uint8Array
}

const ED25519_CURVE = 'ed25519 seed'
const HARDENED_OFFSET = 0x80000000

export const pathRegex = /^m(\/[0-9]+')+$/

// eslint-disable-next-line quotes
export const replaceDerive = (val: string): string => val.replace("'", '')

export const getMasterKeyFromSeed = (seed: Hex): Keys => {
  const h = hmac.create(sha512, ED25519_CURVE)
  const I = h.update(fromHexString(seed)).digest()
  const IL = I.slice(0, 32)
  const IR = I.slice(32)
  return {
    key: IL,
    chainCode: IR,
  }
}

const CKDPriv = ({ key, chainCode }: Keys, index: number): Keys => {
  const indexBuffer = new ArrayBuffer(4)
  const cv = new DataView(indexBuffer)
  cv.setUint32(0, index)

  const data = new Uint8Array(1 + key.length + indexBuffer.byteLength)
  data.set(new Uint8Array(1).fill(0))
  data.set(key, 1)
  data.set(new Uint8Array(indexBuffer, 0, indexBuffer.byteLength), key.length + 1)

  const I = hmac.create(sha512, chainCode).update(data).digest()
  const IL = I.slice(0, 32)
  const IR = I.slice(32)
  return {
    key: IL,
    chainCode: IR,
  }
}

export const getPublicKey = (privateKey: Uint8Array, withZeroByte = true): Uint8Array => {
  const keyPair = nacl.sign.keyPair.fromSeed(privateKey)
  const signPk = keyPair.secretKey.subarray(32)
  const newArr = new Uint8Array(signPk.length + 1)
  newArr.set([0])
  newArr.set(signPk, 1)
  return withZeroByte ? newArr : signPk
}

export const isValidPath = (path: string): boolean => {
  if (!pathRegex.test(path)) {
    return false
  }
  return !path
    .split('/')
    .slice(1)
    .map(replaceDerive)
    .some(Number.isNaN as any /* ts T_T */)
}

export const derivePath = (path: Path, seed: Hex, offset = HARDENED_OFFSET): Keys => {
  if (!isValidPath(path)) {
    throw new Error('Invalid derivation path')
  }

  const { key, chainCode } = getMasterKeyFromSeed(seed)
  const segments = path
    .split('/')
    .slice(1)
    .map(replaceDerive)
    .map((el) => parseInt(el, 10))

  return segments.reduce((parentKeys, segment) => CKDPriv(parentKeys, segment + offset), {
    key,
    chainCode,
  })
}